Issues of Analysis of the Characteristic Times of Vacation Relaxation in Small Solids in the Case of Adsorption and Absorption

摘要

The process of leveling of vacancy density in solids determines the times of reaching the equilibrium state and conditions for using the equations of nonequilibrium thermodynamics, particularly using diffusion equations of atom transport. Issues of characteristic times of vacancy relaxation are analyzed in small single- and two-component solids (granules of solid-phase systems or aerosol particles). The differences in the values of relaxation times are discussed in the case of thermal transport of labels in the processes of self-diffusion and mass transport. It is shown that taking into account the thermodynamic cofactor in the diffusion mass-transport coefficient decreases the relaxation times of processes of the mixing of atoms in two-component mixtures by three or more orders of magnitude, as compared to taking into account the contribution of only the self-diffusion coefficient, while the transport coefficient of vacancies can exceed the self-diffusion coefficients of atoms by three to seven orders of magnitude at the initial stage of the vacancy transport. Size dependences of these relaxation times obtained in the diffusion approximation are considered.